This invention relates to an air bag arranged to deploy by inflow of a gas.
Conventionally, for example, there is used an air bag apparatus provided to a boss portion of a steering wheel main body of a vehicle, and in an instrument panel located at a forward position of a passenger seat. This air bag apparatus includes a bag-shaped air bag, and a cover member covering and receiving the air bag in a non-deployment state. The inflator supplies the gas to the air bag at a collision of the vehicle, and the cover member is broken at predetermined tear lines. Consequently, the air bag is inflated and deployed toward a front side, that is an occupant side of an object to be protected, and the air bag restrains and protects the occupant.
For improving deployment characteristics of the air bag, various structures are employed. It is required to suppress the force applied to the occupant, even in a proximate deployment state that the air bag is deployed when the occupant is closer to the air bag apparatus. For example, Publish Japanese Patent Application, KOKAI No. 2006-51884 shows a structure provided with an air bag which is deployed in a ball shape which has no recessed portion in a case that a tether is not provided, and a tether which serves as a regulation member, which is attached to a fixing portion of the inflator, and which regulates protrusion amount of portion of an occupant side of the air bag to form a recessed portion on a surface on the occupant side. In the structure of the patent document 1, the air bag is deployed on the left and right sides of the occupant, and these both side portions support the occupant. Moreover, the tether to suppress the natural deployment of the air bag is needed to support the air bag against the large force at the deployment.